This invention relates to an improved process for treating metal chlorides and especially such metal chlorides arising as byproducts from the chloride process for making TiO.sub.2.
Large amounts of metal chlorides arise as byproducts from various industrial processes. For example, in the chloride process for making TiO.sub.2, titanium bearing material or ore is chlorinated to produce TiCl.sub.4 and other metal chloride byproducts. Subsequently, the TiCl.sub.4 is separated from the byproducts and is oxidized to the desired TiO.sub.2. The metal chloride byproducts are highly acidic and often contain iron chlorides as the major ingredient. While some of the byproducts can be used as a flocculant to treat waste water, large amounts must be disposed of by neutralization, land filling, deepwelling, etc.
Many processes have been proposed to neutralize and/or stabilize metal chloride byproducts. Further, highly concentrated acidic metal chloride solutions generally are neutralized, followed by solidification or dewatering. However, such processes appear to be deficient because they are both expensive and produce a product which still must be disposed of by landfill or other means, or produce a product for non-demanding applications.
U.S. Pat. No. 5,076,850 provides a step forward by mixing metal chlorides in aqueous solution with alkaline substance. Therein, it had been found that lower density aggregates, with acceptable properties for road base material, are formed when a minimal amount of energy is used to carry out the mixing. The product produced therein is soil-like and substantially not water resistant.